Embodiments of the present disclosure relate to a nonvolatile memory device. More particularly, the present disclosure relates to a storage device that includes the nonvolatile memory device, as well as a memory system that includes such a storage device, and a method of deciding a read voltage of such a storage device.
A storage device (e.g., a solid state drive (SSD)) includes a nonvolatile memory. The storage device with the nonvolatile memory can retain data stored therein even at power-off, and therefore can advantageously store data for a long time. The storage device can be used as main storage in various electronic devices such as a computer, a smartphone, and a smart pad.
The nonvolatile memory of the storage device deteriorates due to various factors. The deterioration can be addressed by varying an operating condition based on the degree of deterioration. Manufacturers of these storage devices address the deterioration so as to adjust a level of a read voltage based on an operating condition of the storage device. However, according to the current methods of addressing deterioration, parameters of a storage device (e.g., read voltage levels) are set based on average usage patterns and use environments. Using average usage patterns and use environments highly restricts the driving environments of the storage devices. Accordingly, storage devices do not always provide optimum operating performances under various environments or deterioration levels.